In some markets, utilities, e.g., electric power companies, are required to bill customers based on the actual cost of the utility commodity, e.g., electric power, at the time of consumption. For example, usage measurements can be required to be made every 15 minutes throughout the day, and bills are generated from the usage measurements based on the cost of power at the time.
One particular approach that has been proposed is a combination of a two-way wireless messaging unit and "smart" electric power meter that can sample power usage every 15 minutes, store the usage information, and then report the usage wirelessly once per day to a central billing entity that has knowledge of the cost of power throughout the day. In the proposed system, each usage sample requires the transmission of 10 bytes of information. A sample is required 96 times per day. Thus, 10.times.96.times.30=28800 bytes per month must be sent from each meter. In a large city, the meter reporting traffic could overwhelm the inbound channel capacity of the two-way messaging system.
Thus, what is needed is a method and apparatus for computing a billable consumption of a utility commodity. Preferably, the method and apparatus will meet the requirement for billing customers based on the actual cost of the utility commodity it the time of consumption, without generating an overwhelming amount of meter reporting traffic.